<template>
  <div class="subject">
    <div>
      <span>{{ item["num1"] }}</span>
      <span>+</span>
      <span>{{ item["num2"] }}</span>
      <span>=</span>
      <input type="number" v-model="sumNum" />
      <button @click="btn(index)">提交</button>
    </div>
  </div>
</template>

<script>
export default {
  props: ["item", "index"],
  data() {
    return {
      sumNum: "",
    };
  },

  methods: {
    btn(index) {
      this.$emit("sum", index, this.sumNum);
    },
  },
};
</script>

<style scoped>
.subject {
  margin: 5px;
  padding: 5px;
  font-size: 20px;
}
.subject span {
  display: inline-block;
  text-align: center;
  width: 20px;
}
.subject input {
  width: 50px;
  height: 20px;
}
</style>